The present invention is generally in the field of therapeutic formulations for delivering gamma-hydroxybutyrate.
Gamma-hydroxybutyrate (xe2x80x9cGHBxe2x80x9d) is a naturally occurring substance that is widely distributed in the mammalian body, being present, for example, in the brain, kidney, heart, liver, lung and muscle (Nelson, et al., J. Neurochem., 37:1345-48 (1981)). When administered exogenously, GHB readily crosses the blood-brain barrier and penetrates the brain, producing a number of neuropharmacological effects. For over 35 years, GHB has been used as an intravenous agent for the induction of anesthesia and for long-term sedation, without serious side-effects on circulation or respiration (Entholzner, et al., Anesthetist, 44:345-50 (1995)), and without an accompanying seizure-inducing activity in humans (Tunnicliff, Clinical Toxicology, 35:581-90 (1997)). Patients with chronic schizophrenia characterized by autism, inactivity, and apathy; catatonic schizophrenia; chronic schizophrenia with hallucination and delusion; atypical psychoses; and chronic brain syndrome due to trauma, as well as neurotic patients (Tanaka, et al., Folia Psychiatrica et Neurologica, 20:9-17 (1966)), have all been treated using GHB. It also has recently been suggested that GHB may be a suitable agent for total intravenous anesthesia in patients with coronary artery disease (Kleinschmidt, et al., Euro. J. Anesthesiology, 14:590-99 (1997)), as well as for sedation during spinal anesthesia (Kleinschmidt, et al., Euro. J. Anaesthesiology, 16:23-30 (1999)).
In addition to these uses, GHB also is used to treat narcolepsy, a chronic sleep disorder that usually begins in adolescence or early adulthood and lasts hroughout life. Narcolepsy is characterized by sudden sleep attacks lasting usually from a few to thirty minutes, paralysis upon lying down or waking, visual or auditory hallucinations at the onset of sleep, and temporary loss of muscle tone while awake (cataplexy) or asleep. Treatment with GHB substantially reduces these signs and symptoms of narcolepsy in humans (Scharf, Sleep, 21:507-14 (1998)).
Other uses of GHB include its application in the pharmacotherapy of alcoholism, where it has been found to reduce alcohol craving and consumption, and to ameliorate symptoms of alcohol withdrawal syndrome in alcoholics (Colombo, et al., Physiology and Behavior, 64:293-302 (1998); Addolorato, et al., The Lancet, 351:38-(1998) and references therein). GHB also reportedly aids patients undergoing withdrawal from opiates (Andriamampandry, et al., Biochem. J. 334:43-50 (1998) and references therein) and relieves anxiety, tremor, and muscle rigidity in patients with Parkinson""s disease (Tanaka, et al., Folia Psychiatrica et Neurologica, 20:9-17 (1966)). Administration of GHB also has been reported to protect neurons and intestinal epithelium against cell death resulting from experimental ischemia (Kaufman and Nelson, Neurochemical Research, 16:965-74 (1991) and references therein), to drop blood pressure in hypertensive patients (Tanaka, et al., Folia Psychiatrica et Neurologica, 20:9-17 (1966)), to increase plasma levels of growth hormone after injection in healthy subjects (Gerra, et al., Int""l Clinical Psychopharmacology, 9:211-15 (1994)), and to stimulate growth hormone and prolactin production (U.S. Pat. No. 5,840,331 to Van Cauter, et al.). Administration of GHB also is purported to be an effective anorectic, heighten sexual desire, produce pleasurable effects such as euphoria and smooth muscle relaxation, promote muscle mass, and be able to induce rapid eye movement sleep (Ropero-Miller and Goldberger, Clinics in Laboratory Medicine, 18:727-46 (1998)). PCT WO 99/09972 and U.S. Pat. No. 5,990,162 to Scharf discloses the use of GHB in treatment of fibromyalgia and chronic fatigue syndrome. Administration of GHB also has been shown to increase gastric emptying (Poggioli, et al., Life Sci. 64:2149-54 (1999)), and could be used as a prokinetic drug for treatment of a number of conditions where improvement in gastrointestinal motility and gastric emptying is desired. Such conditions include treatment of malabsorption disorders, and increased uptake of poorly absorbed drugs. Gamma-butyrolactone which is metabolized to GHB has been shown to potentiate the effect of gamma-aminobutyric acid on gastric secretions (Watanabe, et al., Jpn. J. Pharmacol. 33:1163-69 (1983)). GHB has shown anti-ulcer activity against ulcers induced by indomethacin, restraint stress or pyloric ligation (Yong, et al., Chung Kuo Yao Li Hsueh Po; 10:350-53 (1989)). Other uses of GHB have been described in Tanaka, et al., Folia Psychiatrica et Neurologica, 20:9-17 (1966).
In animals, GHB produces electroencephalographic (EEG) and behavioral changes, resembling generalized absence seizures. The treated animals show arrest of activity which can be aborted by anti-absence drugs. For this reason, GHB has been used to provide a reproducible, consistent, pharmacologically specific model for the study of generalized absence seizures, which is analogous to other models of absence in the rat (Snead, Neuropharmacology, 30:161-67 (1991) and references therein). GHB administration also has been used in animals to normalize cardiovascular function of hemorrhage and as an anti-ischemic (Cash, Neuroscience and Behavioral Rev., 18:291-304, 1994). In mice, GHB was found to exert a radioprotective effect (Cash, Neuroscience and Behavioral Rev., 18:291-304 (1994)).
Infusion of GHB also has been found to possess an angiogenesis inhibitory effect, making GHB potentially useful in the treatment of cancer as an anti- angiogenesis agent (Yonekura, et al., Clin. Cancer Res., 5:2185-91 (1999)). GHB also has been used prophylactically in rats as an antihypoxant, antioxidant, or actoprotector, increasing survival rates of rats with myocardial infarction (Dubovaia, et al., Eksp. Klin. Farmakol. 59:51-54 (1996); Tsorin, et al., Eksp. lin. Farmakol. 56:25-27 (1993)). GHB reportedly prevents heart damage after acute blood loss (Meerson, et al., Kardiologiia 22:38-44 (1982)).
GHB may also be administered prophylactically to reduce inflammation or ischemic or reperfusion injury during surgery. Prophylactic administration of GHB prevented liver damage to tetrachloromethane poisoning (Eksp Kim Farmakol., 59(4):51-54 (1996)). The lithium salt of GHB depressed carrageenan inflammation in a hamster cheek pouch assay (Aleksandrov and Speranskaia, Biull. Eskp. Biol. Med. 106:233-35 (1988)) Prophylactic administration of lithium salt of GHB prevented inflammation in acute paw edema assay (Aleksandrov and Speranskaia, Biull. Eskp. Biol. Med. 103:188-90 (1987)). GHB has been shown to improve blood flow to ischemic heart tissue (Matsievskii, et al., Biull Eksp Biol. Med; 106:531-33 (1988)). GHB also has been used to protect frozen liver tissue for transplantation (Sherman, et al., Transplantation 57:8-11 (1994)).
Sodium 4-hydroxybutyrate has been shown to affect metabolism (Petrin, et al., Vopr. Med Khim, 39:36-39 (1993)), as its administration reduced nucleotide catabolism, glycolysis, lipolysis, and lipid peroxidation. Sodium hydroxybutyrate also has been shown to stimulate the pentosophosphate cycle and interfere with metabolic acidosis (Lopatin, et al., Farmakol. Toksikol, 47:53-55 (1984). Thus GHB may be used to improve me damaging effects of injury, surgery, ischemia and shock.
GHB has been shown to prevent the proliferation of cancer and functions as an antineoplastic agent (Basaki, et al., Gan To Kagaku Ryoho, 27:93-98 2000)). GHB and gamma-butyrolactone have been shown to reduce angiogenesis induced by certain types of cancer cells (Yonekura, et al., Clinical Cancer Research, 5:2185-91 (1999)). GHB also has been shown to be beneficial for the treatment of lung cancer patients during and after surgery (Leonenkov, et al., Vopr. Onkol, 39:75-79 (1993)) and this benefit was attributed to the antihypoxic effects of GHB. Accordingly, GHB can be used to prevent the spread or proliferation of a cancer.
While significant progress has clearly been made in the development of therapeutic and experimental uses for GHB, there have been a number of problems associated with the development of these uses which have hindered or prevented further progress, or made treatment difficult or more burdensome to manage. These problems include the development of hypernatremia and metabolic alkalosis as a result of delivering large doses of GHB, which is administered as a sodium salt rather than a free acid, especially over prolonged periods (Entholzner, E. et al., Anaesthesist, 44:345-50 (1995)). For example, it has been reported that these conditions developed in patients undergoing hemodialysis (Id.). It would therefore be desirable to develop new compositions and methods to deliver therapeutic amounts of GHB in vivo in a form that minimizes or eliminates the use of sodium ion.
In addition to problems associated with the delivery of the salt form of GHB, the half-life of GHB is relatively short (35 minutes, with peak plasma concentration occurring 20-60 minutes after oral administration), requiring more frequent administration of GHB to maintain its therapeutic effects. For example, it has been reported that increasing the dosing of GHB from three times a day to six times a day was beneficial in the treatment of alcoholism (Addolorato, et al., The Lancet, 351:38 (1998)), particularly for a patient population which did not respond well to less frequent dosages. Furthermore, in the treatment of narcoleptic patients, patients were found to benefit from two, or even three, doses of GHB during the night instead of a single dose which left patients wide awake before their planned awakening time (Scharf, Sleep, 21:507-14 (1998)). U.S. Pat. Nos. 4,599,355 and 4,738,985 to Kluger describe the use of ethyl 4-acetoxybutanoate to prolong sleep in a rat, increasing sleep duration with a large dose of this agent from about two hours with GHB to four hours. It therefore would be desirable to develop new compositions and methods to deliver therapeutic amounts of GHB in vivo that were longer acting, reducing the need for more frequent administration. Such formulations would have many advantages, including increased compliance, reduced medical care, and less intrusion, for example, allowing patients under treatment with narcolepsy and alcoholism to sleep uninterrupted.
It would also be desirable to develop new compositions and methods to deliver therapeutic amounts of GHB in vivo that provide a means to control delivery of GHB and plasma levels of GHB more precisely. Such compositions could be useful to raise effective dosages in vivo, as well as to prevent the development of hypernatremia and metabolic alkalosis at current dosage levels.
It is therefore an object of the present invention to provide compositions that deliver therapeutic amounts of GHB in vivo which minimize or eliminate undesirable side effects, for example, associated with co-delivery of sodium ions.
It is another object of the present invention to provide compositions for the deliver therapeutic amounts of GHB in vivo in formulations that are longer acting and reduce the need for frequent administration.
It is a further object to provide methods for delivering such compositions in vivo.
Oligomers and polymer compositions are provided which comprise GHB and produce GHB after administration in vivo. Devices for the storage and delivery of these polymers and oligomers are also provided. These oligomers and polymer compositions are useful in a variety of applications. The compositions can be used therapeutically, for example, in the treatment of patients with narcolepsy, chronic schizophrenia, catatonic schizophrenia, atypical psychoses, chronic brain syndrome, neurosis, alcoholism, drug addiction and withdrawal, Parkinson""s disease and other neuropharmacological illnesses, hypertension, ischemia, circulatory collapse, radiation exposure, cancer, and myocardial infarction. Other uses for the compositions include anesthesia induction, sedation, growth hormone production, heightened sexual desire, anorectic effects, euphoria, smooth muscle relaxation, muscle mass production, and sleep, including rapid eye movement sleep. In a still further embodiment, the oligomers and polymers may be used to produce absence seizures.